Insulation can be used to increase warmth in many different articles of clothing or footwear. In boots designed to be worn in cold and wet conditions, for example, increased amounts of insulation may keep the wearer's feet warm.
Varying amounts of insulation in a type of footwear may be indicated by a weight, for example in grams. More insulation (i.e., a greater weight of insulation) generally provides enhanced insulation and greater warmth.
When insulating footwear designed for vigorous activities, such as hiking or hunting, the amount of insulation can be an important consideration—too much insulation may cause the wearer's foot to overheat and perspire, resulting in blisters and potential injury, while too little insulation may cause the wearer's foot to become cold.
When designing conventional footwear, the goal is to generally provide the footwear with a target overall level or weight of insulation. Footwear designed for colder weather activities will have a greater weight of insulation, whereas footwear for warmer activities will generally have a lighter weight of insulation. This approach, though, fails to consider that different regions of the foot may be better suited to different levels of insulation.